With regard to a control device used in power generation facilities and disaster-prevention infrastructure facilities such as gates and floodgates of a dam, high security characteristics enabling prevention of illegal access and virus entry from outside are required. Meanwhile, in order to achieve operability improvement and quick response in case of trouble, there are cases where acquisition of information from a device, for which high security characteristics are required, via a communication network is required. When such a communication system is established, various types of devices are provided to protect a device for which high security characteristics are required.
For example, there is described a communication system including: a data collection device that is connected to disaster-prevention infrastructure facilities and collects facility data related to the disaster-prevention infrastructure facilities; an intermediate storage device that is provided separately from the data collection device and includes an intermediate storage unit that stores therein facility data collected by the data collection device; a remote monitoring device that can receive the facility data stored in the intermediate storage unit of the intermediate storage device via an external network; and a switch device that can switch a state of the communication system among a disconnection state in which communication between the data collection device and the intermediate storage device is disconnected and communication between the intermediate storage device and the external network is disconnected, a first connection state in which the data collection device and the intermediate storage device are connected to each other to be at least capable of communicating the facility data and the communication between the intermediate storage device and the external network is disconnected, and a second connection state in which the communication between the data collection device and the intermediate storage device is disconnected and the intermediate storage device and the external network are connected to each other to be at least capable of communicating the facility data (Japanese Laid-open Patent Publication No. 2013-195398).
Even when the communication system described in Japanese Laid-open Patent Publication No. 2013-195398 is used, the system can be set in a state of being physically connected to a communication line, and thus there is a risk that a protection-target communication device becomes accessible. Further, by connecting two communication devices communicating with each other via a dedicated line, it is possible to improve the security of these devices; however, if the two devices communicating with each other are provided to be apart, installation of the dedicated line is troublesome.
An object of the invention is to provide a communication connection apparatus that can output data from a protection-target communication device to another communication device with a simple configuration while preventing access to the protection-target communication device, and a communication system including the communication connection apparatus.
According to the present disclosure, there is provided a communication connection apparatus that is configured to control connection of a communication line between at least one first communication device and at least one second communication device, the communication connection apparatus comprising: a first connection port to which a connection line to the at least one first communication device is connected, and which includes a first transmission unit through which a signal output from the at least one first communication device passes and a first reception unit through which a signal to be input to the at least one first communication device passes; a second connection port to which a connection line to the at least one second communication device is connected, and which includes a second transmission unit through which a signal output from the at least one second communication device passes and a second reception unit through which a signal to be input to the at least one second communication device passes; a first connection line that connects the first transmission unit and the second reception unit to each other; and a simulated-signal input unit that inputs, to the first reception unit, a first signal which is a signal for recognizing that the at least one first communication device is connectable to other devices, wherein when the first signal is being input to the first reception unit, the first reception unit and the second transmission unit are physically disconnected from each other.
The above and other objects, features, advantages and technical and industrial significance of this disclosure will be better understood by reading the following detailed description of presently preferred embodiments of the disclosure, when considered in connection with the accompanying drawings.